GxT Ferret 91 2-Channel Labscope - Manual (Page 18)

18
Actuator Tests
Communication Tests
Serial Data
Connect COM probe to serial data ground circuit, engine
block or negative battery post. Connect CH1 probe to
serial data signal from PCM or other control unit. Turn
key on and check DSO display. Digital pulses of varying
frequency and duty cycle should be going by. This
indicates PCM or control unit is alive. Most PCM’s go to
sleep (PCM stops making and sending data) from 6 to 15
seconds after key is shut off. Other vehicle systems will
send serial data for up to 20 minutes after key is shut off.
Secondary Ignition
Connect LabScope KV Adapter to CH2. Connect Cylinder
#1 Pickup to CH1. Connect the Ground Lead on the
LabScope KV Adapter to a good engine ground source
such as the negative battery post or engine block. Connect
the LabScope KV adapter to the Ignition System. Connect
the Cylinder #1 Pickup around #1 Sparkplug wire. With
the key on, engine running, use the throttle or drive the
vehicle to make a misfire or drivability problem occur.
Check waveform for proper shape and amplitude.
On a typical Double Output DIS system, you will have half of the connectors plugged
into the Red side of the LabScope KV Adapter, and the other half plugged into the Blue
side.
The screen above shows what a 6 cylinder DIS engine looks like on the Ferret 91. At
this point, you may use the features of the scope to display and analyze the ignition
waveform.
Distributor Ignitions
All instructions remain the same, except you connect only one KV Clip to the Coil wire.
Do not connect KV Clips to each individual spark plug wire. Simply plug the single KV
Lead into either a Blue or Red connector.
For Distributor ignitions where the coil is in the cap, you will need the appropriate KV
Pickup Plate found in the Available Accessories Section.